Nagar says there are three main reasons ants don't jam up. No. 1, ants don't have egos. They don't show off by zooming past people.

"The second thing is, they do not mind a few accidents or collisions," say Nagar. So unless there's a serious pileup, they just keep going.

The third reason, he says, is that ants seem to get more disciplined when paths get crowded, running in straighter lines and varying their speed less. They're less likely to make unexpected moves in this sort of heavy traffic. It's the kind of steady control you see when a computer, rather than a human, is controlling a car. There's less variability unless it's absolutely called for.

Palca also add that the extent to which marching ants are better than driving humans at avoiding traffic jams is a little unclearin the first place. "Nagar is a physicist, not an ant man," he hedges. "I've talked with ant researchers who say that, for at least some species of ants, one will overtake another on the ant highway. And when the volume of ants is high enough, ants do jam up."

Still, you've gotta hand it to ants
on the collective-intelligence front. If their marching skills are anything like their capacity for teamwork, we could probably stand to learn something from them.